What is placenta?

What is placenta?  Photo from www.sciencephoto.com

The placenta ("afterbirth") — is the most important and absolutely unique body that exists only during pregnancy. It connects the two organisms — mother and fetus, providing it with essential nutrients.

Where is and how it looks placenta?

In normal pregnancy, the placenta is located in the body of the uterus on its back (often) or front wall. It is fully formed to15-16th week of pregnancy, after 20 weeks after starting an active exchange of placental vessels. From 22 to 36 weeks of pregnancy is an increase in placental weight, and at 36 weeks it reaches full functional maturity.

In appearance, the placenta is like a round flat disk. By the time of birth weight of the placenta is 500-600 d — diameter 15-18 cm and a thickness of — 2-3 refer to the placenta distinguish between two surfaces: the mother, adjacent to the wall of the uterus, and the opposite — a fruit.

Function of the placenta

  • First, gas exchange is carried out across the placenta: oxygen penetrates from maternal blood to the fetus, while carbon dioxide is transported in the reverse direction.
  • Secondly, the fetus through the placenta receives nutrients needed for growth and development. It must be remembered that many substances (alcohol, nicotine, drugs, many drugs, viruses) can easily penetrate through it and can have a damaging effect on the fetus. In addition, it can help get rid of the fruit products of their life.
  • Third, placenta provides immunological protection of the fetus, holding cells of the immune system of the mother, who, having got to the fetus and recognizing in it a foreign object could run the reaction of its rejection. At the same time, the placenta passes maternal antibodies that protectfruit from infections.
  • Fourth, placenta plays the role of the endocrine glands and synthesizes hormones (human chorionic gonadotropin (hCG), placental lactogen, prolactin, etc.) necessary to maintain pregnancy, fetal growth.

Normally, the placenta, along with the envelopes (afterbirth) is born through 10-15 minutes after the birth of the fetus. Her carefully inspected and sent to the morphological study. First, very important to make sure that the placenta was born as a whole (that is, on its surface is undamaged and there is no reason to believe that the pieces of the placenta remained in the uterus). Secondly, as the placenta can be seen on the course of pregnancy (if there was any detachment, infectious, etc.).

They want to know about the placenta doctors?

During pregnancy, it is important to identify the signs of impaired function of the placenta — placental insufficiency. To do this during the ultrasound study the structure of the placenta, its location in the uterus, the thickness corresponding to the size of fetal gestational age. In addition, blood flow is studied in placental vessels.

The degree of maturity

This option, as the doctors say, "ultrasound", that is, it depends on the density determined by ultrasound structures placenta.

There are four degrees of maturity placenta:

  • Normally, up to 30 weeks of pregnancy should be determined by the zero degree of maturity of the placenta.
  • The first degree is considered to be acceptable from 27 to 34 a week.
  • The second — from 34 to 39.
  • Since 37 weeks may be determined by the degree of maturity of the third placenta.

In late pregnancy, there comes the so-called physiological aging of the placenta, with a reduction of the area of its exchange surface, the appearance of areas of salt deposits.


Determined by ultrasound. As mentioned above, in normal pregnancy, the placenta is located in the body of the uterus. Sometimes an ultrasound examination in the first half of pregnancy is detected that the placenta is located in the lower parts of the uterus, short or even overlapping region of the internal cervical os. In the future, with the progression of pregnancy, the placenta is often displaced from the top of the lower parts of the uterus. However, if the period of 32 weeks placenta still overlaps the internal os, a condition called placenta previa, which is a serious complication of pregnancy.

Placenta previa can lead to bleeding, which can occur duringII-III trimester of pregnancy or during labor.


Is also determined by ultrasound — placentometry: after establishing the attachment of the placenta sought a site where it has the largest size that is determined. Thickness placenta, as mentioned, increases continuously to36-37 weeks of pregnancy (by this time it is from 20 to 40 mm). Then, it stops the growth and subsequently thickness placenta either decreases or remains at the same level.

The deviation from the norm of at least one of these parameters may indicate trouble in the course of pregnancy.

Like this post? Please share to your friends: